A recent report published in the American Journal of Medical Genetics (Smith et al. 2014) describes a methodical comparison of buccal cells and blood as potential surrogates for brain tissue in epigenomic studies aimed at assessing the methylation status of DNA. The methylation patterns of specific genes are thought to be biomarkers for a variety of psychological disorders and may be the result of such factors such as childhood abuse, malnutrition, and traumatic stress. The authors find that DNA methylation patterns in buccal cells are more similar than blood to those of brain tissue. Certainly it is an attractive notion that permanent changes in the methylation patterns of the genetic code are at least partially responsible for some chronic psychiatric and behavioral traits, but the idea that a simple cheek swab can help unravel these mysteries even better than a blood sample is the part we find the most fascinating.

Rho family GTPases are key regulators in a wide range of physiological processes, including cell motility, cell division, and neuronal development. Rho activity is regulated temporally and spatially by a variety of direct post-translational modifications (PTMs) that include prenylation, ubiquitination, oxidation, nitrosylation, and phosphorylation.

Cytoskeleton Inc. recently released a newsletter highlighting the control of RhoA function through phosphorylation. RhoA is a target for a growing number of kinases and as such, phosphorylation is emerging as a central theme in the regulation of this family of proteins (2).

The newsletter focussed on the mechanism of RhoA phosphorylation at Serine 188, which is mainly conducted by kinases like PKA and PKG (protein kinase A and protein kinase G) which are cyclic AMP-dependent and cyclic GMP-dependent respectively.

Furthermore, it looks at the physiological consequences of RhoA phosphorylation and future directions especially concerning the RhoA PTM involvement in diseases and potential therapeutic options.